Scotland is renowned for the quality of its private and public horticultural collections, and its rich cultural history of plant collecting, allotments and gardening. Horticultural plantings are of significant economic value, as well as providing amenity, health and well-being, cultural and conservation resources. However, pest and pathogens represent a major threat to this highly diverse set of plantings.
Horticultural plantings provide amenity value in public spaces, form structural components of landscaping projects, represent a significant component of urban biodiversity and are central to private, public and heritage gardens. Given the diversity of plants involved in horticulture, there is a corresponding diversity of pests and pathogens of concern, and a particular challenge is the extensive network of plant movement at a range of scales from industrial supply to movement of individual plants between gardens. This results in a highly distributed network of pest and disease vectors. The role of the public is of particular importance for horticulture, in terms of both the ownership of plants in private gardens, and as being a major source of plant movement.
This report sets out estimates for the crop loss and value to Scottish crop production should the molluscicide metaldehyde be withdrawn. This would leave ferric phosphate as the only available chemical control option. Short term losses are negligible as the substitution of ferric phosphate carries no additional treatment costs and has equivalent efficacy. Longer term there is some risk should resistance arise to this single site mode of action active, and ferric phosphate (although of lower mammalian toxicity to metaldehyde) has some environmental impacts of its own.
Heritage gardens play an important role in plant conservation. They house collections gathered over decades or even hundreds of years, including varieties of plants that may be overlooked elsewhere, fostering heirloom varieties and preserving biological diversity that is the raw material of adaptation. As well as being beautiful and tranquil sites of cultural heritage, these ex-situ resources are treasure troves of biological diversity. Arduaine Gardens shows us that tough choices can be necessary and important to preserve these collections and the surrounding environment.